we continue our coverage of the shooting at sandy hook elementary school with john miller. he is a former fbi official and also my colleague at cbs news. also joining us dr. jeffrey lieberman, chairman of psychiatry at columbia university and director of the new york state psychiatric institute and richard aborn of the citizen's crime collision of new york city. i'm pleased to have all of them here. i begin with john miller. so what more do we know this evening about the killer, about his mother, about his motive. >> what we know about the kill certificate that he apparently had planned to do much more an much worse than he actually accomplished, which is hard to fathom. but what we are told now by police are that not only did he have multiple weapons which we knew and not only did they recover multiple shell cases from the shots he fired, but he also possessed, and i'm quoting now, hundreds of rounds of unspent ammunition that he brought with him, possibly with the intent to go through. so this is a school that had 600 students. and apparently he came armed with enough wea